Data transfer device and data transfer system

Abstract

A transfer device according to an embodiment transfers blocks generated by dividing a frame into pieces of data and adding a synchronization header each of the pieces of data. The blocks comprise a first, second and third blocks in this order. The transfer device is configured to acquire a first synchronization header in the first block, a second synchronization header in the second block and a third synchronization header in the third block, judge, in a case where a value of the second synchronization header is incorrect, as to whether or not the value of the second synchronization header can be estimated based on the first and the third synchronization headers so that the second block is consistent with the first and third blocks, and correct the second synchronization header into the estimated value.

What is claimed is: 
     
       1. A data transfer device for transferring blocks generated by dividing a frame into pieces of data each having a first predetermined number of bits and adding a synchronization header having a second predetermined number of bits to each of the blocks, comprising:
 a processing module configured to process an operation of the data transfer device; 
 a buffer for storing the blocks to be transferred; and 
 an interface configured to receive and transmit data to and from the data transfer device, wherein: 
 the synchronization header is configured for synchronization of each of the blocks and has first information for identifying whether the respective block includes a control code other than user data; 
 wherein the blocks comprise a first block, a second block, and a third block that are successively transferred in the stated order; 
 the first block, the second block and the third block include a first synchronization header, a second synchronization header and a third synchronization header as the synchronization header, respectively; and 
 the processing module is configured to:
 acquire the first synchronization header, the second synchronization header, and the third synchronization header; 
 perform, in a case where a value of the first information of the second synchronization header is incorrect, a first judgment as to whether or not the value of the first information of the second synchronization header can be estimated based on the first synchronization header and the third synchronization header so that the second block is consistent with the first block and the third block; 
 judge, in a case where a value of the first information of the first synchronization header and a value of the first information of the third synchronization header is same, that the second synchronization header can be estimated in the first judgment; and 
 correct the second synchronization header into an estimated value of the first information. 
 
 
     
     
       2. The data transfer device according to  claim 1 , wherein:
 each of the blocks contains second information indicating a type of data included therein; and 
 the processing module is configured to:
 perform, in a case where it is judged in the first judgment that the value of the first information of the second synchronization header cannot be estimated, a second judgment as to whether or not the value of the first information of the second synchronization header can be estimated based on the second information included in the first block and the second information included in the third block; and 
 correct the second synchronization header based on a result of the second judgment so as to be consistent with the first block and the third block. 
 
 
     
     
       3. The data transfer device according to  claim 2 , wherein the second information indicating the type of the data is located in a head position of a data part of each of the blocks. 
     
     
       4. The data transfer device according to  claim 1 , wherein the data transfer device is configured to:
 transfer the frame encapsulated by using a Multiprotocol Label Switching (MPLS) label; 
 generate, in a case of being provided at an entrance edge to an MPLS network, the blocks after adding the MPLS label to the frame; and 
 remove, in a case of being provided at an exit edge from the MPLS network, the MPLS label from the frame after attempting to correct at least one of the synchronization headers. 
 
     
     
       5. The data transfer device according to  claim 1 , wherein the processing module is configured to correct the first information of the second synchronization header into the value indicating that the second block contains only user data in a case where the first information of the first synchronization header indicates that the first block contains only the user data and the first information of the third synchronization header indicates that the third block contains only the user data. 
     
     
       6. A data transfer system, comprising at least two nodes, for transferring data therebetween, wherein:
 each of the at least two nodes includes:
 a processing module configured to process an operation of the node thereof; 
 a buffer for storing blocks to be transferred; and 
 an interface configured to receive and transmit data to and from the node thereof; 
 
 each of the at least two nodes is configured to transfer the blocks generated by dividing a frame into pieces of data each having a first predetermined number of bits and adding a synchronization header having a second predetermined number of bits to each of the pieces of data obtained by the dividing; 
 the synchronization header is configured for synchronization of each of the blocks and has first information for identifying whether the respective block includes a control code other than user data; 
 wherein the blocks comprise a first block, a second block, and a third block that are successively transferred in the stated order; 
 the first block, the second block and the third block include a first synchronization header, a second synchronization header and a third synchronization header as the synchronization header, respectively; and 
 each of the at least two nodes is configured to:
 acquire the first synchronization header, the second synchronization header, and the third synchronization header; 
 perform, in a case where a value of the first information of the second synchronization header is incorrect, a first judgment as to whether or not the value of the first information of the second synchronization header can be estimated based on the first synchronization header and the third synchronization header so that the second block is consistent with the first block and the third block; 
 judge, in a case where a value of the first information of the first synchronization header and a value of the first information of the third synchronization header is same, that the second synchronization header can be estimated in the first judgment; and 
 correct the second synchronization header into an estimated value of the first information. 
 
 
     
     
       7. The data transfer system according to  claim 6 , wherein:
 each of the blocks contains second information indicating a type of data included therein; and 
 each of the at least two nodes is configured to:
 perform, in a case where it is judged in the first judgment that the value of the first information of the second synchronization header cannot be estimated, a second judgment as to whether or not the value of the first information of the second synchronization header can be estimated based on the second information included in the first block and the second information included in the third block; and 
 correct the second synchronization header based on a result of the second judgment so as to be consistent with the first block and the third block. 
 
 
     
     
       8. The data transfer system according to  claim 7 , wherein the second information indicating the type of the data is located in a head position of a data part of each of the blocks. 
     
     
       9. The data transfer system according to  claim 6 , wherein:
 the data transfer system comprises a Multiprotocol Label Switching (MPLS) network configured to transfer the frame encapsulated by using an MPLS label; and 
 each of the at least two nodes is configured to:
 generate, in a case of being provided at an entrance edge to the data transfer system, the blocks after adding the MPLS label to the frame; and 
 remove, in a case of being provided at an exit edge from the data transfer system, the MPLS label from the frame after attempting to correct at least one of the synchronization headers. 
 
 
     
     
       10. The data transfer system according to  claim 6 , wherein each of the at least two nodes is configured to correct the second synchronization header into the value indicating that the second block contains only user data in a case where the first synchronization header indicates that the first block contains only the user data and the third synchronization header indicates that the third block contains only the user data.